You still have to add manually the controls to the toolbox. It is a limitation of VS so the only way to currently add Silverlight controls to the toolbox is manually. In the help link you have send me is missed 1 assembly you have to add - Telerik.Windows.Controls.RadScheduler which will allow you to use RadScheduler, everything else is the same so just follow the instructions in the help article and it will be ok .
If you need more help please let me know.
the Telerik team